The present invention relates to devices for handling racks for tubes in an analysis apparatus, in particular an automatic blood analysis apparatus.
The present invention also relates to associated methods for moving said racks in the apparatus.
Hereafter reference will be made essentially to the analysis of blood samples. However, this must not be considered as limitative.
In view of the analysis, the samples, in particular the blood samples are generally contained in tubes. Each tube is hermetically sealed by a stopper which may be pierced. Taking a specimen from the tube is carried out through the stopper, using a sampling needle. For ease of handling, these tubes are arranged in racks. Each rack can for example contain 5 tubes arranged side by side, parallel and substantially in the same plane.
During the movement of a rack in the apparatus, the rack can be subjected to several handling operations. Generally, these handling operations are:                the loading of the rack into the apparatus;        the unloading of the rack, once analyses have been carried out;        the movement of the rack in the apparatus, in particular between a loading position, an analysis position and an unloading position; and,        the agitation of the contents of the tube, with a view to its homogenization. Such homogenization is particularly useful in the case of blood samples, in order to ensure that the sample specimen taken from a tube is truly representative of the contents of the tube.        
Most automated haematology devices use horizontal loading devices. These devices are bulky, expensive and complex. They may moreover, due to their complexity, present problems of reliability. Such loading devices are described in the documents FR2692358 and FR2812088.
Other automatic devices use magnetic vertical loading. Such magnetic loading, in particular described in the document U.S. Pat. No. 4,609,017, requires a metal plate to be fixed onto each rack and uses a pneumatic device to load or unload a rack by a movement from the bottom upwards.
In such loading devices, it is not possible to ensure the agitation of the tubes.
The movement of the racks in an automatic analyzer is generally done linearly, the tubes being substantially vertical and their stopper being at the top. The rack therein is generally guided by rails. In such movement devices, it is not possible to ensure the agitation of the tubes. The document U.S. Pat. No. 4,609,017 describes a movement device using a conveyor belt which also serves as an agitation device. This solution does not allow perfect homogenization. The device is expensive and remains of limited reliability.
For the agitation, apart from the conveyor belt, other devices are described in the documents U.S. Pat. No. 4,921,676, FR2692358, FR2730315, FR2812088, U.S. Pat. No. 4,518,264. They make it possible to agitate one or more tubes removed from a rack, or a rack containing tubes. These devices are expensive and complex. Indeed, they require a mechanism dedicated to agitating the rack or the tubes in the movement device, and a mechanism for withdrawing them, before agitation, then returning them, after agitation.
Once the necessary sampling operations have been carried out in the tubes of a rack, the rack is arranged in a receptacle provided for this purpose. Such devices are described in the documents FR2692358 and FR2812088. The document U.S. Pat. No. 4,609,017 describes a vertical ejection system moved by a pneumatic device.